Molding apparatus



Jan. 5, 1954 M. LARSON MOLDING APPARATUS 2 Sheets-Sheet 1 Filed July 30, 1949 Bnventor A4 AR 7'//v LARS o/v @A y (M01 nel;

Jan. 5, 1954 M. LARSON MOLDING APPARATUS 2 Sheets-Sheet 2 Filed July 50, 1949 3nvcntor MAR T/A/ LARSON B /9 M 8 4 6 Gttorneg Patented Jan. 5, 1954 .MOLDING APPARATUS Martin Larson, Upper Darby, Pa., assignor to Richard H. Prewitt, trading as 'Prewitt Aircraft "Co.,'Wallingf0rd, Pa.

=ApplicationJu1-y30, 1949., Serial No. 1-01,? 18

4 7 Claims. 1

This inizenti'on relates to forming and molding materials and articles, and particularly to moldns and shaping apparatus.

While the art of molding and shaping articles is ancient indeed, there are many shapes and forms-which are irregular, or possessed of various changes in contours, which involve expensive and time-consuming methods for forming a shaping or molding apparatus therefor, and which, therefore are .formidably expensive.

Itis among the objects of the present invention to provide a simple, cheap and accurate apparatus for the manufacture of dies and fixtures tor vforming and shaping. articles and materials; to improve the art of molds; .to provide a quickly assembled forming apparatus which can read- .i-ly he changed toaccord with desired changes in the contour of the shaped article; to provide an improved apparatus I'or shaping articles which isespecial-ly conducive to the introduction-of heat or pressure or both into the shape-forming portions of the apparatus; .to provide improved details of construction of forming apparatus by whichcheaply but accurately .madeimold components can be assembled in hinged relation and arranged for enclosing engagement with the artiicle and. predisposed for locked relation of the mold components during curing of the article; to provide a mold or die which can be partially or Wholly changed in contour quickly and cheapto provide an apparatus which is especially useful in forming certain structural members such, v:for instance, as ,airioils and the like, for aircraft; to provide improved shaping apparatus by which, illustratively, the rotor blade shown .in Prewitt application Serial Number 724,836, can be quickly and cheaply fabricated; .to provide a mold comprisin multiple sections each formed of a plmality of individually -.fabricated laminations; to provide a mold .formed of respectively mating slaminations; to provide a mold having a mold cavity defined y Plural laminations and of greater accuracy than a gouged out mold cavity; to provide a mold of great strength and uniform distribution of stresses; and other advantages become more apparent as the description proceeds. y

In the accompan ing drawings formingpart of thisspeoi-fication:

Eig. 1. represents an exploded. perspective of two complemental portions of a di or shaping apparatus according to a simplified illustrative version of thefinvent'ion, to exemplify the principles incorporated therein;

Fig. .2 represents a transverse section through tion in lowered, seated molding relation to the relatively fixed lower portion thereof;

Fig. '7 represents a fragmentary longitudinal vertical section through the complete mold of Fig. 5, showing the progressiv change in profile 'ofthemold interior lo itudinally of the mold to show one of "the important advantagesthereo'f";

T ig. "8 represents a fragmentary end elevation of "the -mold of Fig. 5: at -the locking end thereof, showing a mecl'ia-nism for forcing the halves together and for retaining them in such .for'ced'association during comifiletihnofthe molding, as 'a supplement to, 'or replacement "of "the "locking pin shown Fig. 5

Fig. "9 represents a fragmentary perspective of a portion of the mold of Fig. 53, with a sect-ion of inflatable or expansible-bag or lik compressive and heating element for insertion into and cooperation With the molding aperture of the mold:

Fig. '10 represents an end elevation *of a mean assembly like that of Fig. 5, modified to show an irregular shape for the'iorm'edarti'cle;

Fig. 11 represents an end elevation of the other end of the mold of Fig. 10, showing that the change in profile or contour of the aperture in the mold, dimensionally progressively of the mold in one dimension, may loe in various directions and proportions.

Fig. 12 represents a -'perspecti-ve of a further modified form of the-invention.

While there are important -additi-on'a1 features and advantages of the structures to be described, it will "be understood that basically the mold comprises upper and lower halves disposed in complemental relation to define together a mold cavity of desired displacement and proportion in the mold, with each moldhalf comprised of a plurality of relatively thin laminations, in-

dividually stamped, and shaped, both as regards the opposite complemental laminations to form the proper sectional profile of the mold cavity or aperture in the respective planes of the aligned laminations, and also individually shaped as regards the laterally adjacent or contiguous laminations, shapes or profiles as to merge thereinto to form a relatively smooth internal mold cavity in the mold portions.

Referring to Figs. 1 to 4 for an exemplification thereof, the mold comprises a lower stationary mold half or portion Ill, having in its upper planar surface II the semi-spherical cavity I2. The movable upper mold portion or half l3 in its lower planar surface l4 carries the semi-spherical convexity I5. Lower half n is formed of a plurality of laminations as of stampings of metal, or of cuttings of wood or the like, of any desired external profile so far as the bottom and sides and ends are concerned, but each having an upper surface arranged to form part of the planar upper surface H, and a portion of the concavity I2. Illustratively, the lower mold may have an end board [6 as a relatively wide terminal lamination. This is for the purpose of spreading tension arising from bolts to be described. To this is juxtaposed an adjacent lamination I! having a slight segmental central depression IS in a larger area of planar portion in the plane of the surface ll. Inwardly of the end board, the next adjacent lamination 2! has a shorter planar portion 22 and a slightly larger shallow depression 23. And so on, to the center of the mold portion, with progressively deepening central depressions and smaller planar portions, and, from the center to the far end, the

reversal thereof. The respective laminations therefor, while each contributing laterally to the strength and solidity of the whole, also define small transverse sections of the total concavity. The upper mold portion I3 is complementally formed with an end board forming a planar portion 25 meeting the planar surface of end board 46 when the mold portions are assembled. Next thereto is lamination 25, having an incomplete planar area 21 interrupted toward the center by the slightly protuberant shallow extension 28, forming the edge of the convexity [5. The next adjacent lamination has a smaller planar area 3| interrupted by the protuberance 3|. The latter is longer and higher than the first protuberance 28, and this progressive increase maintains to the center. When reaching the center the reversal of proportions of laminations begins to form the symmetrical protuberance 5, analogous to the formation of the complemental concavity l2.

The multiple 1aminations of the bottom or lower mold portion In are held together suitably by through bolts or the like, and preferably the connectors comprise heating pipes 35, extending through all of the laminations of mold portion Ill and held tightly therein by nuts 36. Similarly, the upper mold portion is held together by a plurality of steam or like heating pipes 31, clamped by nuts 38 bearing tightly against the sides of mold portion I3.

The mold cavity in this illustrative case comprises the slight space 40 between the meeting confronting surfaces of the respective concavity and convexity. With such an illustrative mold a semi-spherical dimple or protuberance can be formed in a sheet of material, such as metal or plastics or the like, with the proper application of pressure between the two halves of the mold. In the illustrative case the laminations preferably are in respective alignment in common planes, with a lamination in the bottom half complemental in shape to the lamination of the upper half.

It will be seen that it is a cheap and expeditious proceeding to take a plurality of unformed laminations, such as of boards, and cut the top or bottom edge surface to the upper configuration to form the desired overall shape of mold or shaping device, when respectively as sembled in the proper juxtaposed order with properly cut contiguous boards in series. Sheet metal or plate metal stamping can similarly be formed and assembled. The greater the accuracy desired, the thinner the respective laminations. Preferably, in addition to the through bolts, the sheets or laminations are secured together with adhesive or the like.

The anchoring of the component laminations by means of a heating pipe arrangement secures the solidity and practical homogeneity of the mold halves, with the additional virtue of impressed heat for heating material within the aperture 40 of the assembled mold. This renders the mold highly efficient in shaping a sheet of plastic or the like, or in setting thermosetting adhesives or the like.

In the preferred exemplification in which the article to be shaped is relatively elongated, as. purely illustratively, in the formation of a rotor blade or the like, the same principle of laminar construction is utilized, but in detailedly different manner. Thus, referring to Fig. 5, a fixed support, such as elongated rail or the like t? is provided, of I beam construction, having an upper flange surface 46. In substantial relative parallelism, in generally evenly spaced relation longitudinally of the surface 45, are the plurality of triangular supporting plates 4?, each having a single pivot pin aperture #38, with the several apertures in alignment longitudinally of the series, to receive and support an elongated pintle pin 56. Pin 5!] forms the pivotal connection between the fixed lower half mold portion and the arcuately adjustable upper half mold por tion it, to be described.

Starting with the left side of the device of Fig. 5, the lower half of the complete mold is defined by the end lamination 5i, having single upwardly projecting eye 52 at the pivot end for receiving the pintle 5i] upon which it is threaded. The upper surface of the lamination below the eye 52 comprises the planar upper edge 53 interrupted by the shaped depression or molding cavity-forming recess 54. The lower edge of the lamination 5| includes at least one of the feet 55, to support the lower mold half of the surface 46 of the I beam 45. The lamination 5| is provided and all other laminations of the lower mold portion 39 are provided with a series of transverse apertures for purposes to be described. Attached inwardly to the end lamination 5! of the lower mold portion 49 in horizontal substantial alignment therewith, is the sub-lamination 56, formed at the upper and lower edge similarly to the analogous edges of the lamination 5 l. The left hand end of the sub-lamination is provided with the upwardly projecting locking eye 58, to receive the locking pin 50. The lamination 5i and sub-lamination 56 considered as a unit have a single eye for pivotal swinging, at one end of the unit, and a single eye for locking at the other end of the unit. 'These components and the others to be described are secured together by adhesives or the like. The lower mold portion is completed by a series, of: alternate laminsmns and sublaminations, all secured togethen The upper :portion or mold 153-, starting at the left side in Fig. 5, comprises the l-snbelaminm tion '65 having the lower surface formedof the planar edge cs on opposite sides of, the recess: complemental to the oppositely extending. re es 54 of the lower lamination =54, lower lamination and upper sub-iamination es arein common vertical planes normal to the pivot pin iii.

The upper sub lamination 5 preferably terminates at the end remote from pivot pin 53. in the downwardly projecting looking. eyeii l. illhe sub-lamination 35 is juxtaposed to aligned laterally in part with the "lamination having the lower surface aligned laterally geneml-ly in mold relation to the lower edge of'fthesub-lamination 65?, lying vertically the plan of the corresponding lower sub-lamination. The upper lamination l'e is preferably provided with the downwardly projecting pivotal ll. through which :the "-pintleefi passes. The upper mold por- :ti'on 39 is formed of alternate laminatlons and sub-laminations. The entire mold, formed of the relatively pivoted upper and lower mold portions 39 and :49 is thus formed of alternate :full and partial laminations, i. e., with lamina-Hons and sub-' lamina'tions, so that spaced ehordwisely of the mold there are a plurality of aligned respectively upwardly and downwardly projecting .pivot eyes on one side, and a plurality of aligned respectively upwardly and downwardly project- :ting locking eyes, at the other side of the mold. From time :to time, longitudinally of the mold,

a pivot eye as recited is omitted, to permit the insertion into the plane of that lamination of one of the triangular supporting "plates The "upper and lower mold portions 35} and ill define the mold cavity 40".

The respective laminations and sub-laminations of each half are transvers'ely bored or pierced as at T3 "with all of'the respecoiveapertures in alignment so as "to receive the long itw :dinally extending anchoring or bonding rods 15, and .the heat-conducting "pipes or tubes F5. "Through this means the halves are held rigidly in material shaping and forming relation while suitable heat can loe introduced as to maintain "the Work under suitable elevated temperatures.

It is a feature of the invention that the mold portions and mold cavities as provided be arranged for or susceptible ts association with .expansible elements, in order either to increase the molding or sealing pressures at selected points or areas-or to form internal cores between and the mold cavity surfaces, the work can be compressed. Especially is this a feature in conjunction with the introduction of heat 't'hereinto. Thus, referring to '9, :an illustrative dorm thereof, the mold portions define one mold cavity M3" and an inflatable hollow has 8%! is provided, collapsible upon itself for insertion into and .:removal from the mold cavity dill. The bag :30 may be such as to fiil the mold "cavity when or to fill selected portions only there-0i, relying upon inert more or less solid and rigid filling blocks to fill the remaimim of the 'It been observed that the specific profile or contour .of' the mold cavity will :be that necessary for the particular problem involved It (Dibviously need not he that of an airioil as Eileen illustrated certain of "the -figures. I-elerring to Figs. 1i) and 11, the mold :cayzity dil may be irregular and asymmetrical and of "diflerent. profiles at diferent along the meld 6 ins disclosed rat imeqrcspectioe 11915 of the mold. will live accessions that --whereas with the mual smolding sir-sleeping problem, the use of the :mindiolholdithe parts tightly :assembleld relation muyrlcepreierred, in the .form, for instancasimwnin 5sthisismotessentia1. In

.lEig. .8 an alternative or additiv form of mechanism is shown. cormarises a G clamp 81 the and adjustable plunger 82, daytime wheel 83. The G clamp 81, or a series whereof spaced longitudinally :of the mold, are each disposed, to enga e the upper and lower mold spnntlonsifi and, and with suitable :znanipulations to gradually iorce the halves to- :gether toexent molding mshapmg pressur upon mmtcziiai in the :mold cavity. This pressure can he maintained by the clamps, if desired, or can foe assumed day the locking ,pin Bil, and the clamps removed for use on :another mold.

lltu ill be apparent ithat the -mold portion comprised solely and scompletely of ,slaminations as shown in the "previously described figures is not the only @exemplificution of the invention that maybe made. For instance, as shown in Fig. 12, a rectangular frame $1) is provided carrying, for instazmze, the guide pins M, (as, of course, may also be .proyided :in the other forms of the invention to insure proper registration of the componerrtpartsL in rectangular central openaithe plurality of properly surfaced :and proportioned leanmations 93 @are mounted and are squeezed together into :a. rigid :die member by the end plate 34., tlne ccmpression of which is controlled .lsy the thumb screws i95. The assembly rests .upon the rigid base plate 96,, and forms :a

die member ifior the restricted surface disclosed.

In this connection it will be clear that the idle membereonstnucted as disclosed herein does not necessarily need a. complemental die portion and a mold cavity.

The Ruminations can :be used to build up any desired form of single donning member, with reference to which shaping and forming can occur. fillhus, the laminated shape constructed 1 in accordance with this invention can be associated the hydraulic or fluid pressure diaphragmatic ,miess such success at the present in shaping sheet and other metal and like articles to condemn to single male entities. Theeingle die is forced against a sheet of metal, hacked byn toug-h rubber diaphragm, and the latis subjected to Ztfigh hydraulic pressure to Force condemnation of thesheet of metal against the male member under the enclosing pressure of diaphragm.

it will :he understood that wherever used in the specification and claims, rthe adhesives is zmheordedmo be broad enough to cover glues, cemerits, thecmosetting land thermoplastic compounds, brazing, soldering, and other :lorms of more or less permanent attachment of the laminations toeachicther. .In some cases ithe attachment of one laminations, as in Fig. 1 can be 'purelyifrictional "without adhesives or theneqnivalenis, upon external lateral pressure to maintain the alignment, and this is of particular value when the running (or shaping part must be dismounted for removal from the shaped artiicle' dorm, or .fcrj -qmck changes in contours.

Having imiention, 1 claim:

mold formedpf acomplemental mold poreach mold portion being :fiormed of a plurality of laminaticns haying ears one end, and subalam l-nations short of said ears of said said laminatinns sublaminations being disposed in alternating lateral juxtapositioning to form a mold portion, means holding the respective laminations and sub-laminations in tight lateral juxtaposition, said cars at said one end of the laminations of one mold portion being disposed to support a pivot pin, a pivot pin, said ears at one end of said other mold portion being disposed to pivotallyengage said pin to relatively pivot the mold portions together with interleaving of the respective ears to maintain the rigidity of the mold portions.

2. A mold formed of complemental mold portions, each mold portion being formed of a plurality of laminations each having an car at one end, and sub-laminations each having an ear at the other end, said laminations and sub-laminations being disposed in alternating lateral juxtapositioning and each stopping transversely of the mold portion short of the ear of the other to form a substantially solid mold portion having aligned ears on each side separated by the thickness respectively of the laminations and the sublaminations, said ears at said one end of the laminations of one mold portion being disposed to support a pivot pin, a pivot pin, said ears at one end of the laminations of said other mold portion being disposed to pivotally engage said pin to relatively pivot the mold portions together with inter leaving of the respective ears to form a substantially solid column of ears at the pivot line, said ears at the said other end of the respective sublaminations being disposed to permit securing the mold portions together with interleaving of cars forming a substantially solid column of ears opposite to said pivot pin by a locking pin, and a. removable locking pin engaging said last men tioned ears.

3. A mold formed of complemental mold portions, each mold portion being formed of a plurality of laminations having cars at one end, and sub-laminations each having an ear at the other end, said laminations and sub-laminations being disposed in alternating lateral juxtapositioning bonded together with adhesives to form a mold portion, said ears at said one end of the laminations of one mold portion being disposed to support a pivot pin, a pivot pin, said cars at said one end of said other mold portion being disposed to pivotally engage said pin to relatively pivot the mold portions together, said ears at said other end,

of the respective sub-laminations being disposed to permit securing the mold portions together opposite to said pivot pin by a locking pin, a removable locking pin engaging said last mentioned ears, and means for rigidly holding the respective laminations and sub-laminations of the respective mold portions together.

4. A mold formed of complemental mold portions, each mold portion being formed of a plurality of laminations having ears at one end, and

sub-laminations each having an car at the other end, said laminations and sub-laminations being disposed in alternating lateral juxtapositioning to form a mold portion, said ears at said one end of the laminations of one mold portion being dis-v posed to support a pivot pin, a pivot pin, said ears at said one end of said other mold portion being disposed to pivotally engage said pin to relatively pivot the mold portions together, said ears at said other end of the respective sub-laminations being disposed to permit securing the mold portions together opposite to said pivot pin by a locking pin, a removable locking pin engagin said last mentioned ears, and means for locking the -respective laminations and sub-laminations of the respective mold portions together, said locking means comprising heat conducting threaded tubes passing through the laminations and sublaminations.

5. A mold formed of complemental mold portions, each mold portion comprising a plurality of laminations of substantially uniform thickness throughout their lengths, in alternation with a plurality of sub-laminations of the same uniform thickness throughout their lengths, the laminations including ears at a first common side of the complemental portions extending in the plane of the respective laminations beyond the sub-laminations at said first common side, the sub-laminations including ears at a second common side extending in the plane of the respective sub-laminations beyond the said laminations, the ears of the laminations of one portion extending between the ears of the laminations of the complemental portion in assembly and the ears of the sub-laminations of one portion extending between the ears of the sub-laminations of the complemental portion of the mold in assembly, said laminations and sub-laminations having transversely aligned registering surfaces to define in assembly a smooth-surfaced mold cavitv, the respective laminations being in aligned relation transversely of the mold cavity with the respective subdaminations, means for holding the complemental mold portions in assembly, said last means at the first common side comprising registering apertures formed in the respective aligned ears of the laminations, and a pin disposed in the respective registerin apertures,

6'. A mold formed of complemental portions defining a smooth surface mold cavity, each portion comprising a plurality of laterally juxtaposed laminations and sub-laminations of substantially equal and uniform thicknesses throughout, each of the plurality having sur-- faces defining portions of said smooth surfaced mold cavity, portions of the laminations spaced from the mold cavity-defining surfaces thereof comprising first ears, with said first ears extending beyond the respective interposed alternate sub-laminations in general alignment sub stantially longitudinally of the mold at a first common side of said mold, portions of the sublaminations spaced from the mold cavity-defining surfaces comprising second ears, with the said second ears extending beyond the respective interposed alternate laminations in general alignment substantially longitudinally of the mold at a second common side of said mold, means compressing the said plurality transversely of the respective laminations and sub-laminations to form each portion as a rigid entity having two series of aligned respectively spaced ears at the sides of each mold portion, with the spacing between contiguous ears of said uniform thickness, said portions in assembly interleaving the said first ears at said common first side and said second ears at said second common side to form two substantially solid columns of ears at the said sides, and means for holding the mold portions in such assembly.

7. A mold formed of complemental portions defining a smooth surfaced mold cavity, each portion comprising a plurality of laterally juxtaposed laminations and sub-laminations of substantially equal and uniform thicknesses throughout, each of the plurality having surfaces defining portions of said smooth surfaced mold cavity, portions of the laminations space. from the mold cavity-defining surfaces thereof comprising first ears, with said first ears extendin beyond the respective interposed alternate sublaminations in general alignment substantially longitudinally of the mold at a first common side of said mold, portions of the sub-laminations spaced from the mold cavity-defining surfaces comprising second ears, with the said second ears extending beyond the respective interposed alternate laminations in general alignment substantially longitudinally of the mold at a second. common side of said mold, means compressing the said plurality transversely of the respective laminations and sub-laminations to form each portion as a rigid entity having tWo series of aligned respectively spaced ears at the sides of each mold portion, with the spacing between contiguous ears of said uniform thickness, said portions in assembly interleaving the said first ears at said common first side and said second ears at said second common side to form two substantially solid columns of cars at the said sides, means for holding the mold portions in such assembly, supporting means, and a supporting ear mounted on the supporting means having the same said uniform thickness, one of said laminations terminating short of and providing a space 7 between adjacent first ears, said supporting ear disposed in said space to complete the said solid 16 column of overlapping interleaved ears at said first side of the mold While supporting the mold at said side.

MARTIN LARSON.

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